1. Field of the Invention
The present invention relates to an ingot support device for slicing silicon. In particular, the present invention relates to an ingot support device for slicing silicon having further improved properties and which can be produced at a low cost.
2. Description of the Related Art
Conventionally, silicon wafers have been produced by slicing a single crystal block (ingot block) using piano wire. More particularly, for example, a cylindrical ingot block is mounted on and secured to an ingot support device using an adhesive such as an epoxy resin, and the ingot block is sliced to a desired thickness using piano wire while applying a cutting oil and/or a cutting powder, thereby, producing multiple silicon wafers.
FIG. 2 is an illustration of a prior art ingot support device for slicing silicon. The ingot support device 10 comprises a carbon mounting block 50 to mount and secure an ingot block 3, and an underlying glass base 60. In the production of silicon wafers, the ingot block 3 is secured to the carbon mounting block 50 of the ingot support device 10 using an adhesive, then piano wires 4 are advanced in a fixed direction to cut the ingot block 3 into silicon wafers. At this time, cutting oil and/or cutting powder are applied in order to facilitate the cutting of the ingot block 3. The piano wires 4 cut the carbon mounting block 50 together with the ingot block 3, and when the piano wires 4 reach the glass base 60, it is determined that the cutting of the ingot block 3 is completed, and the cutting process is stopped.
The drawbacks of the above-mentioned conventional ingot support device 10 for slicing silicon are that it is expensive and the production process is complicated because the ingot support device is a composite of the carbon mounting block 50 and the glass base 60. In addition, carbon used for the ingot support device is expensive since it should have high quality. Moreover, the use of the glass base 60 may also present a problem with on-the-job safety due to breakage and the like.
As semiconductor devices have become highly integrated recently, chip area has increased. Consequently, the diameters of silicon wafers have also increased. Presently, 8-inch silicon wafers are the main stream, but it is expected that the size will be increased to around 16-inch, for example, in the future. The increase in the diameter of silicon wafers will require the upsizing of the ingot block, and the ingot support device for slicing silicon will correspondingly be required to have increased strength and a larger size to mount and secure such an ingot block.
Accordingly, an object of the present invention is to provide an ingot support device for slicing silicon which can be produced easily at a low cost, which has enough strength to cope with the upsizing of the ingot block, has high adhesive properties with the ingot block, and has other further improved characteristics which are required of the ingot support device for slicing silicon such as oil resistance, insulating properties, a low thermal expansion coefficient, etc.
As the result of extensive study, the present inventors have been able to solve the above-mentioned conventional problems.
In one aspect of the present invention, there is provided an ingot support device for slicing silicon produced by molding a molding material comprising an acrylic resin and one or more inorganic fillers selected from the group consisting of aluminium hydroxide, barium sulphate, barium carbonate, calcium carbonate and silica.
In another aspect of the present invention, there is provided an ingot support device for slicing silicon produced by molding a molding material comprising an unsaturated polyester resin and one or more inorganic fillers selected from the group consisting of aluminium hydroxide, barium sulphate, barium carbonate, calcium carbonate and silica.
In a further aspect of the present invention, there is provided the ingot support device for slicing silicon in which the blending ratio of the inorganic fillers is 40-85% by weight based on the total amount of the molding material.
In a yet further aspect of the present invention, there is provided the ingot support device for slicing silicon in which the blending ratio of the inorganic fillers is 55-80% by weight based on the total amount of the molding material.
In a still further aspect of the present invention, there is provided the ingot support device for slicing silicon in which the acrylic resin is polymethyl methacrylate resin.
In a still further aspect of the present invention, there is provided the ingot support device for slicing silicon in which the surface roughness of the surface which the silicon ingot is mounted on and secured to is in the range between 10 and 1000 xcexcm, according to JIS B0601-1982.
In a still further aspect of the present invention, there is provided the ingot support device for slicing silicon in which the surface roughness is 20-200 xcexcm.